Membrane guided tissue regeneration is new biological concept. The basic theory of this concept includes the belief that during the healing process of wound, the different cells will show different speed of cell migration and regeneration in the wound. If an appropriate membrane being placed to form a mechanical barrier, so that only the needed cells can grow into that area and prevent others from going in, thus resulting in the creation of a guided area where the needed cells can undergo proliferation and differentiation under protection in completing an ideal tissue regeneration and repair. In this article, the experimental researches on the application of membrane guided tissue regeneration in the repair of tubular bone defects, skull defects and faciomaxillary defects were reviewed from literatures, and the degradable and non-degradable materials were introduced, particularly. The pros and cons of this method and the materials were evaluated. It is believed that this technique will push forward the progress in bone biology and reconstructive surgery.
OBJECTIVE To confirm membrane-guided tissue regeneration in the healing course of segmental bone defects and study the mechanism. METHODS Segmental, 1 cm osteoperiosteal defects were produced in both radii of 12 rabbits. One side was covered with hydroxyapatite/polylactic acid(HA/PLA) membrane encapsulated as a tube. The contralateral side served as an untreated control. Healing courses were detected by radiographic and histologic examinations. RESULTS All control sides showed nonunion, whereas there were consistent healing pattern in test sides. CONCLUSION Membrane technique can promote bone regeneration.
Objective To evaluate the effects of surgical treatment for severe ocular rupture with blood staining of cornea and non-light perception , and analyze the relative factors. Methods Seven severely rup tured eyes of 7 patients with blood staining of cornea and non-light perception underwent second-stage penetrating keratoplasty combined with vitrectomy using temporary keratoprosthesis. All injured eyes had blood staining of cornea, hemorrhage in anterior chamber and vitreous, and choroidal and retinal detachment before the second-stage surgery. The average interval of the two surgical stages was 18 days (12-21 days). The preoperative visual acuity was non-light percept ion in all injured eyes with the mean intraocular pressure of 3 mm Hg (1 mm Hg =0.133 kPa) (2-5 mm Hg).The mean follow-up period was 12 months (6-30 months). Results The postoperative visual acuity was better than light perception in 5 eyes with the best corrected visual acuity of light perception to 0.06. The retina was attached in 5 eyes (5/7). The mean postoperative intraocular pressure was 12 mm Hg(5-15 mm Hg)which was significantly higher than the preoperative one (Plt;0.05). Postoperative complications mainly included temporary intraocular hypertension (1 eye), corneal neovasculariza tion (4 eyes), cornea rejection (4 eyes), and ocular atrophy (2 eyes). Conclusion Penetrating keratoplasty combined with vitrectomy using temporary keratoprosthesis is a safe and effective method in treating severe ocular rupture with blood staining of cornea and non-light perception. (Chin J Ocul Fundus Dis，2004，20：212-214)
Objective To investigate the effect of repairing bone defect with tissue engineered bone seeded with the autologous red bone marrow (ARBM) and wrapped by the pedicled fascial flap and provide experimental foundation for cl inicalappl ication. Methods Thirty-two New Zealand white rabbits (male and/or female) aged 4-5 months old and weighing2.0-2.5 kg were used to make the experimental model of bilateral 2 cm defect of the long bone and the periosteum in the radius. The tissue engineered bone was prepared by seeding the ARBM obtained from the rabbits on the osteoinductive absorbing material containing BMP. The left side of the experimental model underwent the implantation of autologous tissue engineered bone serving as the control group (group A). While the right side was designed as the experimental group (group B), one 5 cm × 3 cm fascial flap pedicled on the nameless blood vessel along with its capillary network adjacent to the bone defect was prepared using microsurgical technology, and the autologous tissue engineered bone wrapped by the fascial flap was used to fill the bone defect. At 4, 8, 12, and 16 weeks after operation, X-ray exam, absorbance (A) value test, gross morphology and histology observation, morphology quantitative analysis of bone in the reparative area, vascular image analysis on the boundary area were conducted. Results X-ray films, gross morphology observation, and histology observation: group B was superior to group A in terms of the growth of blood vessel into the implant, the quantity and the speed of the bone trabecula and the cartilage tissue formation, the development of mature bone structure, the remolding of shaft structure, the reopen of marrow cavity, and the absorbance and degradation of the implant. A value: there was significant difference between two groups 8, 12, and 16 weeks after operation (P lt; 0.05), and there were significant differences among those three time points in groups A and B (P lt; 0.05). For the ratio of neonatal trabecula area to the total reparative area, there were significant differences between two groups 4, 8, 12, and 16 weeks after operation (P lt; 0.05), and there were significant differences among those four time points in group B (P lt; 0.05).For the vascular regenerative area in per unit area of the junctional zone, group B was superior to group A 4, 8, 12, and 16 weeks after operation (P lt; 0.05). Conclusion Tissue engineered bone, seeded with the ARBM and wrapped by the pedicled fascial flap, has a sound reparative effect on bone defect due to its dual role of constructing vascularization and inducing membrane guided tissue regeneration.
The hallmark lesions of age-related macular degeneration (AMD) are drusen and basal linear deposit which are lipid substances deposited in Bruch membrane or the compartment on the Bruch membrane. There is a prevailing hypothesis that lipid and its oxidized derivant deposited in retina may have important roles in the pathogenesis of AMD. Lipid oxidation products are toxic, may affect the adjacent cells, induce inflammation, and trigger neovascularization.7-ketocholestoral (7KCh), a naturally occurring oxidized form of cholesterol, had been found to be toxic to retinal cells and able to induce chronic inflammation, which may play a critical role in the development of AMD. However the precise mechanism remains to be elucidated. Thus we will make a brief review of 7KCh and its association with AMD.
ObjectiveTo observe the effect of non-vitrectomy in the treatment of idiopathic macular epiretinal membranes (IMEM).MethodsThis study is a randomized controlled trial. From December 2017 to December 2018, 60 IMEM patients (60 eyes) diagnosed in Weifang Eye Hospital were included in the study. BCVA, intraocular pressure (IOP) and OCT were performed in all patients. The BCVA examination was performed using the international standard visual acuity chart, which was converted to logMAR. The CMT was measured by OCT. According to the surgical methods, the patients were divided into non-vitrectomy group and control group, 30 patients (30 eyes) in each group. The age (t=1.723), logMAR BCVA (t=1.703), CMT (t=-0.956), IOP (t=-1.434) were not significantly different between the two groups (P=0.090, 0.094, 0.343, 0.157). 23G vitreous cutting system was used in all eyes. The macular epiretinal membranes was removed by non-vitrectomy in the non-vitrectomy group and by vitrectomy in the control group. The relevant examination with the same equipment and methods before the operation at 1 week and 1, 3, 6 months after operation. The time of surgery, the changes of BCVA, CMT and postoperative complications in the two groups were observed comparatively. Variance analysis of repeated measurements was performed for the comparison of BCVA, CMT and IOP after surgery in the two groups. Wilcoxon rank sum test of two independent samples was performed for the degree of vision improvement. The incidence of postoperative complications was compared by χ2 test.ResultsAt 6 months after operation, BCVA increased in 24 eyes (80%) and unchanged in 6 eyes (20%) in the non-vitrectomy group. Compared with preoperative BCVA, the difference was statistically significant (P＜0.05). BCVA increased in 25 eyes (83.4%), unchanged in 4 eyes (13.3%) and decreased in 1 eye (3.3%) in the control group. Compared with preoperative BCVA, the difference was statistically significant (P＜0.05). There was no significant difference between the two groups in BCVA improvement degree after operation (Z=－0.26, P＞ 0.05). At 6 months after operation, the average logMAR BCVA was statistically significant compared with the preoperative in the non-vitrectomy group (P=0.002, 0.005) and control group (P=0.004, ＜0.001). Visual stability occurred 1 month after operation in the non-vitrectomy group and 3 months after operation in the control group. The effective operative time of the non-vitrectomy group and control group was 4.50±1.41 and 15.50±2.33 min, respectively. The difference of effective operation time between the two groups was statistically significant (t=－22.12, P＜0.05). After surgery, no significant complications were found in the non-vitrectomy group. In the control group, there were 3 eyes with low IOP and 1 eye with macular hole during operation.ConclusionsNon-vitrectomy and vitrectomy have similar effects on IMEM. Non-vitrectomy has short effective operation time, faster recovery after surgery and no obvious complications.
ObjectiveTo investigate expressions and biological function of membrane type matrix metallopro-teinase-1 (MT1-MMP) and matrix metalloproteinase-2 (MMP-2) in papillary thyroid carcinoma. MethodsThe expre-ssions of MT1-MMP and MMP-2 in 164 cases of papillary thyroid carcinoma and paracancerous tissues were detected by immunohistochemistry.The association between the expressions of MT1-MMP and MMP-2 and clinicopathological characteristics of papillary thyroid carcinoma was analyzed. ResultsIn paracancerous tissues, the positive expression rate of MT1-MMP was 11.0% (18/164), and the positive expression rate of MMP-2 was 14.0% (23/164).In papillary thyroid carcinoma tissues, the positive expression rates of MT1-MMP and MMP-2 was 61.6% (101/164) and 67.7% (111/164), respectively.The expressions of MT1-MMP and MMP-2 in carcinoma tissues and para carcinoma tissues were statistically significant differences (P < 0.05).The expressions of MT1-MMP and MMP-2 in papillary thyroid carcinoma tissues correlated with the lymph node metastasis (P < 0.05).In addition, the expression of MMP-2 in papillary thyroid carcinoma tissues correlated with capsule invasion (P < 0.05).The positive correlation was found between the expressions of MT1-MMP and MMP-2 in papillary thyroid carcinoma tissues (r=0.256, P < 0.05). ConclusionsMT1-MMP and MMP-2 may be involved the thyroid capsule invasion and lymph node metastasis of papillary thyroid carcinoma.MT1-MMP and MMP-2 may be involved in the progression of papillary thyroid carcinoma.
OBJECTIVE The human epidermal cells were bred on a kind of bio-membrane, the bio-brane, in engineering a kind of new epidermal substitute, the bio-membrane bred cell graft. METHODS Fresh and frozen grafts of biomembrane bred epidermal cells were transplanted into the full-thickness wounds of nude mice and those received simple Bio-brane were served as control. The wounds of the two groups were observed daily and biopsy was taken on the 3, 5, 7, 10, 21 and 35 days respectively. RESULTS Epidermal cells could be cultured in vitro on the bio-membrane reaching the sub-saturated state of 60 to 70 percents. The bio-membrane after being grafted the epidermal cells continued to proliferate and differentiate to form a layer of new epidermis. There was no difference between the fresh and the frozen bio-membranes. CONCLUSION Bio-membrane bred with epidermal cells could be a kind of ideal epidermal substitute.
OBJECTIVE To repair long bone segmental defects using biodegradable poly epsilon-caprolactone (PCL) and polylactic acid(PLA) co-polymer membranes, and explore its role and mechanism in guided bone regeneration (GBR). METHODS Rabbit radial segmental defects (1.2 cm in length, retain the periosteum) were created in this study, 24 animals were divided into 2 groups. The membranes were used to enclose the defects in experimental group, and no treatment in control group. After 3, 6, and 12 weeks of operation, X-ray, gross and histological examinations were observed. RESULTS The bone regeneration of experimental group was better than that of control group. Three weeks after operation, obvious external callus along the membrane were found in experimental group, and bony linking composed of external callus bridge were found in 6 weeks after operation. After 12 weeks of operation, callus bridge outside the membrane and bony reunion inside the membrane were achieved in experimental group. While in control group, typical nonunion was observed after 6 weeks of operation. CONCLUSION Guided bone regeneration can be achieved by using biodegradable membrane. The defects are repaired by the means of outside membrane callus and relatively late inside membrane callus. The membrane can prevent the ingrowth of fibrous tissue into defect area, thus nonunion are avoid, and keep a high concentration of nutritive elements, also serve as a frame for osteocyte growth to enhance bone healing.
ObjectiveTo observe the changes of the structure and visual function of the retina in patients with or without the ectopic inner foveal layers (EIFL) and to explore the factors influencing the recovery of visual function in patients with idiopathic epimacular membrane (IMEM).MethodsA retrospective clinical study. From March 2015 to June 2019, 90 patients with MEM who were diagnosed by Ophthalmic Center of the Second Hospital of Hebei Medical University were enrolled in the study. All patients were examined by best corrected visual acuity (BCVA) and frequency domain optical coherence scan. BCVA was recorded by Snellen vision table, and it was converted into the minimum resolution angle logarithm (logMAR) vision. Among 90 eyes, IMEM grade 2-4 was 68 (75.6%, 68/90), 18 (20.0%, 18/90), 4 (4.4%, 4/90), respectively. According to this, the grade 2 was set as group A, and the grade 3 and grade 4 were combined to group B. There was no significant difference in age (t=0.015), sex composition ratio of patients between two groups (χ2=0.060) and the average of central macular thickness (CMT) (F=2.277) (P=0.904, 0.809, 0.141). The difference of average logMAR and BCVA was statistically significant (F=35.913, P=0.000). All patients underwent 25G pars plana three channel vitrectomy with simultaneous removal of epiretinal membrane and internal limiting membrane. BCVA, CMT and improvement of IMEM grading were observed at 1, 3, 6 and 12 months after operation. BCVA, EIFL thickness and CMT were compared before and after operation by single factor repeated variance analysis; Fisher exact probability method was used to compare the changes of the anatomical structure of the eyes in the two groups at 12 months after operation.Results1, 3, 6, 12 months after operation, the average eyes of logMAR BCVA in group A were 0.50±0.13, 0.38±0.12, 0.27±0.12, 0.19±0.10. The patients in group B were 0.66±0.14, 0.60±0.13, 0.54±0.14, 0.52±0.14. CMT in group A were 364.82±81.29, 281.65±72.45, 228.55±55.34, 182.84±56.13 μm. The patients in group B were 455.88±69.60, 440.18±68.65, 383.76±65.38, 371.39±66.60 μm. The difference was statistically significant in the two groups (BCVA: F=37.913, 11.479, 24.250, 39.013; P=0.000, 0.002, 0.000, 0.000. CMT: F=10.987, 39.610, 55.789, 79.987; P=0.002, 0.000, 0.000, 0.000). In group A, IMEM was improved to 57 eyes of grade 1 on 12 months after operation. Among the 18 eyes in group B, IMEM was improved to 1 and 3 eyes in level 1 and level 2, respectively, and no improvement was found in 4 eyes in grade 4. The difference was statistically significant (P=0.000) in the improvement of the number of eyes in the two groups.ConclusionsThe patients with IMEM without EIFL have better visual prognosis and reversible anatomical changes. EIFL is an important factor affecting the visual function and anatomical structure recovery after operation.